CausesBy Mayo Clinic staff
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|Parts of the immune system|
A lymph node is a small, round or bean-shaped cluster of cells covered by a capsule of connective tissue. The cells are a combination of lymphocytes — which produce protein particles that capture invaders, such as viruses — and macrophages, which break down the captured material. Lymphocytes and macrophages filter your lymphatic fluid as it travels through your body and protect you by destroying invaders.
Lymph nodes are located in groups, and each group drains a specific area of your body. You may be more likely to notice swelling in certain areas, such as in the lymph nodes in your neck, under your chin, in your armpits and in your groin. The site of the swollen lymph nodes may help identify the underlying cause.
The most common cause of swollen lymph nodes is an infection, particularly a viral infection, such as the common cold. However, there are other types of infection, including parasitic and bacterial, and other possible causes of swollen lymph nodes. They include:
- Strep throat
- Ear infections
- Infected (abscessed) tooth
- Skin or wound infections, such as cellulitis or erysipelas
- Human immunodeficiency virus (HIV) — the virus that causes AIDS
- Certain sexually transmitted diseases, such as syphilis
- Toxoplasmosis — a parasitic infection resulting from contact with the feces of an infected cat or eating undercooked meat
- Cat scratch fever — a bacterial infection from a cat scratch or bite
Immune system disorders
- Lupus — a chronic inflammatory disease that can target your joints, skin, kidneys, blood cells, heart and lungs
- Rheumatoid arthritis — a chronic inflammatory disease that targets the tissue that lines your joints (synovium)
- Lymphoma — cancer that originates in your lymphatic system
- Leukemia — cancer of your body's blood-forming tissue, including your bone marrow and lymphatic system
- Other cancers that have spread (metastasized ) to lymph nodes
Other possible, but rare causes include certain medications, such as the anti-seizure medication phenytoin (Dilantin), and preventive medications for malaria.
- Armitage JO. Approach to the patient with lymphadenopathy and splenomegaly. In: Goldman L, et al. Cecil Medicine. 23rd ed. Philadelphia, Pa.: Saunders Elsevier; 2008. http://www.mdconsult.com/das/book/body/224582198-6/0/1492/0.html. Accessed Oct. 29, 2010.
- Fletcher RH. Evaluation of peripheral lymphadenopathy in adults. http://www.uptodate.com/home/index.html. Accessed Dec. 6, 2010.
- Henry PH, et al. Enlargement of lymph nodes and spleen. In: Fauci AS, et al. Harrison's Principles of Internal Medicine. 17th ed. New York, N.Y.: McGraw Hill Medical; 2008. http://www.accessmedicine.com/content.aspx?aID=2875326. Accessed Dec. 6, 2010.
- Lymphadenitis. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/sec10/ch119/ch119j.html#sec10-ch119-ch119j-691. Accessed Dec. 5, 2010.
- Mohler ER, et al. Lymphedema: Etiology, clinical manifestations, and diagnosis. http://www.uptodate.com/home/index.html. Accessed Dec. 6, 2010.
- Rosenberg TL, et al. Evaluating the adult patient with a neck mass. Medical Clinics of North America. 2010;94:1017.
- Anderson CF (expert opinion). Mayo Clinic, Rochester, Minn. Dec. 7, 2010.